Re: [PATCH] erofs: add error log in erofs_fc_parse_param

From: Gao Xiang
Date: Fri Jan 17 2025 - 04:55:53 EST




On 2025/1/17 17:50, Chen Linxuan wrote:
On Fri, 2025-01-17 at 17:28 +0800, Gao Xiang wrote:
Hi Linxuan,

On 2025/1/17 16:52, Chen Linxuan wrote:
While reading erofs code, I notice that `erofs_fc_parse_param` will
return -ENOPARAM, which means that erofs do not support this option,
without report anything when `fs_parse` return an unknown `opt`.

But if an option is unknown to erofs, I mean that option not in
`erofs_fs_parameters` at all, `fs_parse` will return -ENOPARAM,
which means that `erofs_fs_parameters` should has returned earlier.

Entering `default` means `fs_parse` return something we unexpected.
I am not sure about it but I think we should return -EINVAL here,
just like `xfs_fs_parse_param`.

Signed-off-by: Chen Linxuan <chenlinxuan@xxxxxxxxxxxxx>

I think the default branch is actually deadcode here, see
erofs_fc_parse_param() -> fs_parse() -> fs_lookup_key() -> -ENOPARAM

then vfs_parse_fs_param() will show "Unknown parameter".

Maybe we could just kill `default:` branch...

ext4 do not have a `default:` branch, but xfs return -EINVAL.

I think `default:` branch can report error when `fs_parse` or
`erofs_fs_parameters` goes wrong.

How can it go wrong?

Thanks,
Gao Xiang